[Vwdiesel] hard brakes

[Libbybapa at wmconnect.com]

In a message dated 6/19/06 10:18:10 PM US Mountain Standard Time, 
vegbenz300 at gmail.com writes:


> Well the belt looks and feels fine.
> I've not been able to find any sort of diapraghm replacement for the brake
> booster online.
> 
> What do you mean by freeplay?
> 

I don't think that you will find any diaphragm replacement for the booster.  
It is said to be non-repairable and just replaceable as a unit.  If anyone 
mentioned a diaphragm kit for the brakes they would have been referring to the 
vacuum pump diaphragm kit.  Many/most pumps are the rotary version and so do not 
have a diaphragm in them.

The freeplay is the amount of play in the pedal prior to it engaging 
anything.  The way the brake booster system works is that normally it receives vacuum 
to both sides of the booster diaphragm and so is in balance.  Once the brake 
pedal is depressed it opens a port to atmosphere on one side of the booster and 
so the vacuum on the other side of the booster pulls the plunger against the 
master cylinder.  If there is not enough freeplay in the pedal then the 
booster will always act against the MC and so constantly apply some braking force 
that varies with the amount of vacuum that the vacuum pump is pulling.

Andrew